We are now in the process of preparing phosphatid fractions and cell wall skeletons from BCG bacilli according to the method of Azuma, et al. The fractions will be tested singly and in combination to determine whether or not resistance to growth of syngeneic melanoma cells and mammary adenocarcinoma cells can be promoted by either fraction alone or in combination. The tumor cells will be administered either intravenously or intraperitoneally to normal mice and animals immunized with either viable BCG or fractions derived from these organisms. Recently, we have received a sample of MER which we are to test for its ability to produce nonspecific resistance to tumors.